1. Field of the Invention
The present invention relates to a building suitable for application to a nuclear power plant, and more particularly, to a building structure and its construction method.
2. Description of the Related Art
Reinforced concrete (RC) construction, steel-framed reinforced concrete (SRC) construction or a combination of these two constructions are typically used for the structures of the reactor buildings and turbine buildings at nuclear power plants. However, since the buildings at this type of facility are required to have much higher levels of safety and reliability than in the case of ordinary structures, extremely rigid structures are required. Thus, since the wall and slab thicknesses are considerably thicker in comparison with ordinary buildings, and the amounts of iron and steel reinforcing members are much greater, construction costs are inevitably higher and the construction period is longer.
FIGS. 13 and 14 show an example of the design of this type of reactor building. This building consists of RC construction for the below ground portion and lower levels of the above ground portion, SRC construction for the upper levels, and steel frame (S) construction for the roof, and has a structure in which cylindrical containment vessel 2 is arranged in the center of the outer peripheral wall 1, the planar shape of which is nearly square, and columns 3, beams 4, slabs 5 on each floor and earthquake-resisting walls 6 are provided on multiple floors around its periphery. Reference symbol 7 indicates a foundation plate, 8 a pressure vessel, 9 its pedestal, 10 a diaphragm floor inside the containment vessel 2, 11 a top slab of the containment vessel 2, 12 a pool wall for providing pool P above containment vessel 2, 13 an operating floor, and 14 a roof truss. In addition, examples of the pool P include a spent fuel pool (SFP) and a dryer and separator storage pool (DSP).
This type of reactor building is constructed in the form of a wall member having a reinforced concrete construction in which the outer peripheral wall 1 has a thickness of about 0.3-2 meters, and the containment vessel 2 has a thickness of 2 meters. In addition, various types of numerous equipment and apparatuses are installed on each floor inside the building constructed in this manner. When constructing such a reactor building having this large size as well as complex structure and form, a construction period is required that is roughly twice as long as thermoelectric power plants of the same size. In particular, since the structural member of each floor and the structural member of the pool P and so forth are integrally provided around and above the containment vessel 2, its form becomes complex and the conditions under which stress is generated also become complex. As a result, construction is extremely difficult and intricate.
In contrast, there has been a request in recent years to shorten construction time during the construction of nuclear power plants, and various structures and construction methods have been developed in order to realize this. However, an effective structure and construction method that is able to realize a significant shortening of construction time have yet to be developed.
In consideration of the above circumstances, the object of the present invention is to provide a building and its construction method that are particularly suitable for nuclear power plants and so forth, and which are capable of realizing a significant shortening of construction time at the time of their construction.
The present invention relates to a building used for a nuclear power plant and characterized in that a wall portion which forms at least apart of the building is formed from a megawall structure of steel plate reinforced concrete construction that is composed by pouring concrete into megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of the building.
For example, a wall member which forms an outer peripheral wall of the building is formed from the megawall structure of steel plate reinforced concrete construction that is composed by pouring concrete into megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of the building.
According to this building, since the wall member is formed from the megawall structure of steel plate reinforced concrete construction, the ease of construction can be considerably improved as compared with reinforced concrete construction and steel-frame reinforced concrete construction of the prior art, and the form of the structural member can be simplified and abbreviated. As a result, construction time can be shortened considerably.
Alternatively, in the present invention, a structural member which is composed of the wall member and a floor member of the building is formed from the megawall structure of steel plate reinforced concrete construction composed by combining megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of the building for forming the wall member and megablocks composed of outer shell steel plates for forming the floor member, and by pouring concrete therein or there above.
According to this building, in addition to the megablocks for the wall member, since megablocks are also used for forming the floor member, and the structural member composed of the megawall structure of steel plate reinforced concrete construction is formed by combining these megablocks, the ease of construction is further improved, thereby making it possible to further shorten construction time.
In case of construction of the building, the megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of the building are produced in advance followed by forming an outer shell of the wall member using these megablocks, and then the wall member composed of the megawall structure of steel plate reinforced concrete construction is formed by pouring concrete into the above megablocks.
Alternatively, in case of construction of the building, the megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of the building for forming the wall member of the building, and megablocks composed of outer shell steel plates for forming the floor member of the building, are produced in advance followed by forming an outer shell of the structural member by combining these megablocks, and then the structural member composed of the megawall structure of steel plate reinforced concrete construction is formed by pouring concrete into and above these megablocks.
According to these methods, the wall member or structural member composed of a megawall structure of steel plate reinforced concrete construction is formed simply by forming outer shell of a wall member or structural member by assembling megablocks produced in advance followed by pouring concrete. Thus, the building can be constructed extremely efficiently, and the construction time can be shortened considerably.
Furthermore, an equipment module may be provided inside the building. This equipment modules is composed of steel frames formed by support columns that have a height equivalent to the plurality of floors and function as columns inside the building and floor frames that are supported by the support columns and function as floors in the building, and various types of equipment to be installed in the building that are provided in the steel flames along with their ancillary piping.
According to this building, construction of the columns and floors of the building as well as installation of equipment can be carried out collectively simply by installing the equipment module in the building. Thus, the building can be constructed extremely efficiently and the construction time required for constructing the building and installing equipment can be shortened considerably.
In this case, the equipment module preferably being self-standing in the above building, and the horizontal force that acts on the equipment module is preferably supported by the structural member of the building which surrounding the equipment module.
According to this building, since a structure is employed in which the horizontal force that acts on the self-standing equipment module is supported by the surrounding structural member, it is not necessary to give horizontal bearing force to the equipment module themselves. Thus, the steel frames only require a simple, lightweight structure.
In this case, it is preferable that the structural member surrounding the equipment modules is composed of the megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into megablocks composed of outer shell steel plates.
When the building is a reactor building provided with a pool above a containment vessel, a peripheral wall of the containment vessel is extending upward to form a pool outer peripheral wall that has a cylindrical shape when viewed from overhead, and a pool inner peripheral wall is provided on a top slab of the containment vessel so as to be concentric with the pool outer peripheral wall, and as a result, a ring-shaped pool employing the top slab for its bottom is integrally provided with the containment vessel.
According to this building, since the ring-shaped pool is integrally provided with the containment vessel above the containment vessel, the form of the structural member above the containment vessel can be simplified considerably as compared with reactor buildings of the prior art. Thus, the ease of construction is improved significantly, and construction time can be shortened considerably. Moreover, since the upper structure of the containment vessel is simplified, the status of stress generation in that section is improved and the pool has the effect of reinforcing the containment vessel, thereby allowing the obtaining of favorable results in terms of structure as well.
In this case, it is preferable that the containment vessel and pool are composed of a megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into megablocks composed of outer shell steel plates.
According to this building, since the formwork and work for providing reinforcing bars are omitted due to the use of steel plate reinforced concrete construction, the ease of construction can be improved considerably and construction time can be shortened considerably.
In addition, the containment vessel and pool outer peripheral wall are preferably separated from the peripheral structural member and made to stand alone.
According to this building, by isolating the containment vessel and pool outer peripheral wall from the surrounding structural member and allowing them to stand alone, it is no longer necessary to join the two structural members, and work for providing the two structural members can be carried out independently. As a result, a rational process can be compiled during building construction, thereby making it possible to shorten construction time even more.